Large Solar Optical Telescopes

Large aperture is a necessary but not sufficient condition for high resolution observations. Other requirements include optical quality, site selection, and a telescope design that takes best advantage of the site. The ultimate resolution limit of an optical telescope depends on the aperture and the wavelength of light being observed and is caused by diffraction. Adaptive optics can now allow ground-based telescopes to reach their diffraction limits. Space-based telescopes reach their diffraction limits much more easily. Somewhat arbitrarily we have defined 50 cm aperture as large in the following list.

The physically largest solar telescopes are fixed telescopes with very long focal lengths. These provide the most convenient arrangements for performing experiments. In the list these are designated as tower telescopes. Spar telescopes (by "spar" we mean a telescope in which the first focus moves around rather than being at a fixed observing table) of the same aperture can provide equal resolution, however. With coude feed optics, spar telescopes can also provide fixed laboratory spaces as tower telescopes do.

This list is incomplete. First we list telescopes with aperture of 50 cm or larger, then some smaller telescopes of interest.

NameTypeAp. DateLocation
Under construction or proposed
DKIST RS 424cm 2020? Haleakala
EST RS 4 meters ? Canary Islands
CLST RS 176cm (clear aperture) ? western China
CGST RS 500 - 800 cm ? western China
National Large Solar Telescope RS 200cm ? Ladakh, India
COSMO RS 150cm ? Mauna Loa, Hawaii
Operational as of April 2019
GREGOR RS 150cm 2010 Tenerife
BBSO GST RS 160cm 2009 Big Bear
SST (Swedish Solar Telescope) rT 100cm 2002 La Palma
Fuxian Solar Observatory NVST RS 98cm 2013 Fuxian Lake, China
Sunrise Rb 100cm 2007 New Mexico
Themis RT 90cm 1996 Tenerife
Crimea RT 90cm 1973 Crimea, Ukraine
Sayan RT 80cm 1979 Sayan, Russia
Baikal LVT rT 76cm 1978 Lake Baikal, Russia
SPO VTT (now Dunn Telescope or DST) RT 76cm 1969 Sunspot
German VTT (Vacuum Tower Telescope) RT 70cm 1987 Tenerife
Snow telescope RT 61cm 1904 Mt. Wilson
Einsteinturm (Einstein Tower) rT 60cm 1924 Potsdam, Germany
Hida Domeless Solar Telescope RT 60cm 1979 Takayama, Gifu, Japan
Meudon RT 60cm 1968 Meudon, France
Huairou Multi-Channel Telescope RS 60cm 1994 Huairou, China
Crimea coronagraph cS 53cm Crimea, Ukraine
Sayan coronagraph cS 53cm Sayan, Russia
Hinode (Solar-B) Rs 50cm 2006 low Earth orbit
SOLIS VSM (vector magnetograph) RS 50cm 2004 Temporarily not in service, being installed at Big Bear.
Solar-C (off-axis coronagraph) CS 50cm 2001 Haleakala
Yunnan Solar Spectral Telescope RS 50cm Kunming, China
Abastumani coronagraph cS 50cm Abastumani, Georgia
Pic du Midi rS 50cm 1972 Pic du Midi, France
Other solar telescopes of interest
SDO HMI rs 14cm 2010 geosynchronous orbit
Dutch Open Telescope (DOT) RS 45cm 1997 La Palma
KIS tower refractor rT 45cm Schauinsland, Germany (nr. Freiburg)
German VNT (Vacuum Newton Telescope) R 40cm Tenerife
Marshall SFC RS 30cm Huntsville
Mt. Wilson 150-foot tower rT 30cm 1912 Mt. Wilson
Mees IVM (vector magnetograph) rS 28cm 1992 Haleakala
Mees coronagraph cS 25cm Haleakala
Mt. Wilson 60-foot tower rT 1907 Mt. Wilson
SMARTrS 2x25cm, 2x20cm 2003 Hida Observatory, Japan
SOHO MDI rs 12cm 1995 L1 Lagrange point
GONG rT 3cm 1995 Big Bear, Mauna Loa, Learmonth, Udaipur, Tenerife, Cerro Tololo
No longer in service
McMath-Pierce Telescope (shut down 2018)
Main RT 160cm 1962 Kitt Peak
East Auxiliary RT 81cm 1962 Kitt Peak
West Auxiliary RT 81cm 1962 Kitt Peak
San Fernando Observatory (closed 2016) RS 61cm 1969 Sylmar
Evans Solar Facility (coronagraph, closed 2014) cS 40cm 1953 Sunspot
TRACE (not visible light, shut down 2010) Rs 30cm 1998 low Earth orbit
Kitt Peak Vacuum Telescope (replaced by SOLIS VSM) RT 70cm 1973 Kitt Peak
BBSO (removed 2006, replaced by GST) RS 65cm 1973 Big Bear
Swedish VTT (Vacuum Tower Telescope, replaced by SST) rT 50cm 1985 La Palma
McGregor 75-foot tower telescope, operation ended 1979 RT 1940 Lake Angelus, Michigan
50-foot tower, McMath-Hulbert Observatory, operation ended 1979 RT 40cm 1936 Lake Angelus, Michigan
10.5 inch, McMath-Hulbert Observatory, replaced in 1941 RS 26cm 1930 Lake Angelus, Michigan
German GCT (Gregory Coude Telescope, replaced by GREGOR) R 45cm Tenerife
BBSO "10 inch" (removed 2006, replaced by GST) rS 25cm 1970 Big Bear


r = refractor
R = reflector
c = refractor coronagraph
C = reflector coronagraph
b = balloon
s = spacecraft
S = spar (or some other type of pointed telescope)
T = tower (generally a fixed telescope with a heliostat, coelostat, or turret)

For example, RT means a reflecting tower (or other fixed) telescope and Rs means a reflecting telescope on a spacecraft.

u.c. = under construction

U.S. solar telescope locations:
Kitt Peak is in Arizona.
Sunspot is in New Mexico.
Big Bear, Mt. Wilson, and Sylmar are in California.
Haleakala is on the island of Maui in Hawaii.
Mauna Loa is on the island of Hawaii in Hawaii.
Huntsville is in Alabama.

Other popular locations:

La Palma and Tenerife are in the Canary Islands which belong to Spain.
Learmonth is in Australia.
Cerro Tololo is in Chile.
Udaipur is in India.

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© BBSO/NJIT - Last modified: April 24, 2019.